ABSTRACT The overall goal of this 5-year R21/R33 grant proposal, ?Geriatric Oncology Research Infrastructure to Improve Clinical Care,? submitted on behalf of the Cancer and Aging Research Group (CARG), is to establish a sustainable national research infrastructure to facilitate and support significant innovative projects addressing key interdisciplinary research questions at the aging and cancer interface. This proposal addresses a key scientific priority highlighted in PAR 16-367, the ?development of research infrastructure to facilitate clinical studies involving geriatric cancer populations.? Despite the rapid growth of the older adult cancer population, there is a substantial unmet need to coordinate resources, expertise, and data to support research at the aging and cancer interface. The Principal Investigators (Multi-PIs) of this proposal, Drs. Dale, Hurria, and Mohile, recognized this need and embarked on two major efforts. First, in 2007, they led the creation and development of CARG (www.mycarg.org), a coalition of investigators dedicated to: 1) linking existing interdisciplinary aging and cancer researchers together; 2) supporting the development of high quality aging and cancer research; and 3) fostering new researchers in aging and cancer. Remarkably, this grassroots approach has created success beyond its modest, mostly local resources. Second, the Multi-PIs secured a 5-year U13 grant (U13 AG038151; PI: Hurria, co-PIs: Mohile and Dale) ?Geriatric Oncology Research to Improve Clinical Care,? in collaboration with the National Institute on Aging and the National Cancer Institute which supported 3 conferences, bringing together national leaders to identify research priorities in aging and cancer. The development of CARG and the identification of research priorities through the U13 grant set a solid foundation; however, to accelerate research efforts, a more robust infrastructure is needed to facilitate and foster interdisciplinary, collaborative research in aging and cancer, focus on the career development of investigators to grow the field, and widely disseminate the research findings. Therefore, the aims of the proposal are to: 1. Solidify the infrastructure and expertise, in the form of Cores, needed to facilitate the design of impactful aging and cancer research based on U13 priorities; 2. Utilize the sustainable infrastructure to foster collaborations among a range of interdisciplinary investigators across the nation to accelerate innovative research in aging and cancer; 3. Support and guide high-priority research projects at the interface of aging and cancer to lay the foundation for competitive multi-site studies; 4. Identify, cultivate, and mentor investigators in aging and cancer research; and 5. Disseminate through effective communication strategies the research findings and data-sharing opportunities to the larger community. Ultimately, these proposed activities will lead to a sustainable infrastructure that supports high-impact research aimed at improving the care of older adults with cancer.